11-17-2020 10:54 AM
Hi,
i have a strange beahaviour after configuring the BMA280 slope detection. I am using INT1 as the associated interrupt and after configuring it in temporary latched mode (e.g. 500ms) the pin switches to low periodically for a short amount of time even if the condition for the slope detection is met permanently. The time between these periodically peaks is the configured latch-time ( i tested it with several configurations).
I hope someone can help.
Regards,
Christof
11-19-2020 10:45 AM - edited 11-19-2020 10:47 AM
Hi Sir:
Do you mean that you use 4.7.5 Slope / any-motion detection?
I verified this feature, and maybe found the same phenomenon you said.
I think it is normal, because in the temporary mode an asserted interrupt and selected pin are cleared after a defined period
of time if you don't read int_status registers, you can browse BMA280 datasheet to know it more.
Please see the 4.7.1 General features and Figure 6 in the datasheet.
If you don't want the pin switches to low , you should choose latch mode.
11-19-2020 01:47 PM
Hi,
"Do you mean that you use 4.7.5 Slope / any-motion detection?"
Yes, thats the one I used
"I think it is normal, because in the temporary mode an asserted interrupt and selected pin are cleared after a defined period
of time if you don't read int_status registers, you can browse BMA280 datasheet to know it more.
Please see the 4.7.1 General features and Figure 6 in the datasheet."
Looks like i missed this sentence in the Datasheet but in figure 6 it looks like the latch time is triggered after the internal signal from interrupt engine switches to low. Therefore I would expect the interrupt pin to stay high as long as the internal signal never turns low and to trigger the latch-time afterwards.
Nonetheless, as you can verify this behaviour i expect it to be normal for latched interrupts.
11-23-2020 08:27 AM
If you don't read int_status register, the interrupt pin keep high in latch mode after slope interrupt occur.